The bonding of H to Fe is analyzed using qualitative electronic calculations in the framework of the atom superposition and electron delocalization orbital cluster method (ASED-MO). Upon introduction of a stacking fault in FCC Fe, the changes in the electronic structure are studied when a pair of hydrogen atoms are located near the fault. A cluster of 180 metallic atoms distributed in five layers represents the solid. The interstitial H atoms arc positioned in accordance with previous studies. The Fe-H interaction decreases the Fe-Fe bond strength and the H effect is limited to the first Fe neighbor. An analysis of the orbital interaction reveals that the Fe-H bonding involves mainly the Fe 4s and H 1s orbitals. The orbital population analysis reveals some H-H association, which is more important than that obtained in dislocated Fe. A comparison is given with H pairs located near BCC Fe dislocations or vacancies. (C) 2002 International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserved.